Al Leiter might be leaving the Mets, but he might not be leaving their division.

The Mets could be on the verge of seeing Leiter, their longtime lefty, sign with an NL East rival. The pitcher is in discussions with the Marlins, both sides confirmed yesterday.

One Miami report even indicated that a deal might be wrapped up as early as today.

The 39-year-old Leiter has been a Met since 1998 and was all but assumed to return for his final season in 2005. But the Mets did not pick up Leiter’s $10 million option for 2005, buying him out for $2 million and breaking off talks with him last week.

The Mets then turned their pitching focus to Pedro Martinez, leaving Leiter as a potential free-agent target of the Yankees. But now it appears Leiter is poised to leave New York and return to Florida, where he pitched in 1996-97.

“I view him as a Met. To see him go somewhere else, he’s going to be missed,” Joe McEwing said yesterday when asked about Leiter’s likely departure. “The way he takes the ball every fifth day and prepares every fifth day and the way he is in the clubhouse, he’s going to be missed.”

On the Pedro Martinez front, the two sides spoke yesterday, but the pitcher’s camp has not submitted its counterproposal yet to the Mets’ offer.

If Leiter does sign with Florida, it would likely mean the Marlins will wave goodbye to free agent pitcher Carl Pavano. The righty will visit the Yankees this weekend, but nothing is planned with the Mets while he’s in town.